Answer:
Explanation:
x -4 , 3x-11 , 5x - 18 ,.......
first term = a = x -4
Common difference (d) = second term - first term
= 3x -11 - [ x - 4]
= 3x - 11 - x + 4
= 3x - x - 11 + 4
= 2x - 7
nth term = a + (n-1)*d
12th term = x - 4 + 11*(2x - 7)
= x - 4 + 11*2x - 7 *11
= x - 4 + 22x - 77
=x + 22x - 4 - 77
= 23x - 81